On speaking out about climate change: “I think I have a civic responsibility to communicate to whoever will listen about issues around climate change, particularly climate change and the Great Barrier Reef.”

On the IPCC’s warning of coral reef decimation: “I think the figures – the 70% to 90% gone with another half a degree of global average warming, above the 1C we’ve already experienced – are on the more pessimistic end of the spectrum.

On the 2017 bleaching event: “We saw less bleaching in year two. The reason it didn’t bleach so much in year two was because all the heat-susceptible ones had died.”

On projecting coral loss: “The assumption of many climate models is that the same level of recurrence of heat will have the same biological response and that’s not necessarily true.”

On “techno-fixes” to coral bleaching: “There’s been a ridiculous amount of money, about half a billion dollars, put into a whole crockery of schemes – most of which are pretty laughable.”

Carbon Brief: First of all, you’re originally from Ireland. How did you first get into the study of coral reefs?

Terry Hughes: Yeah, I grew up in Ireland. It’s a long story. As a teenager, I learned to dive in Ireland in kelp beds. Pretty cold water. When I went to university, I went to Trinity College in Dublin. I taught one of my lecturers how to dive and so the following summer we both went off to Jamaica to a very famous marine lab called Discovery Bay Marine Lab. I ended up going there most summers for the next 20 years. I first saw a coral reef when I was about 20, and compared to Ireland the water was clearer and warmer so, as a budding marine biologist, working on the water in the tropics seemed like a pretty good deal and a lot easier – so I became interested in coral reefs. Certainly, they’re fascinating ecosystems and it’s relatively easy to spend a lot of time underwater in the tropics compared to most places.

CB: And you’ve been studying the Great Barrier Reef since the 1990s? Is that right?

TH: I moved to Australia in 1990, so I’ve actually been here longer than anywhere else. I grew up in Ireland, I left when I was about 21, I lived in the States for 12 years and then I came here because of the opportunity of working on the Great Barrier Reef. In the time that I spent in the Caribbean, which was the late 70s through to the mid-90s, the reefs I were studying in Jamaica became more and more degraded – so I’m sort of an ecological fugitive in search of a pristine coral reef, so I came to Australia. And, tragically, the same sort of degradation that we’ve seen much earlier elsewhere around the world is now unfolding very quickly in the Great Barrier Reef.

CB: Can you describe, from the 1990s to today, what kind of changes you’ve seen across the Great Barrier Reef?

TH: The 1990s, of course, is not the starting point of the decline of most of the world’s coral reefs. That began centuries ago. High numbers of people generally is associated with heavy fishing and with pollution, declining water quality – near cities especially and that’s been ongoing for centuries. Two of the three main stresses on coral reefs are local: overfishing and pollution. Those haven’t gone away. In fact, they’re still escalating in most places, but we now have a third big stress on coral reefs and it’s global – and, of course, that’s climate change. The insidious thing about climate change is there’s nowhere to hide from it. So, even the most pristine, most remote place that’s otherwise unaffected by people – like the northern Great Barrier Reef – for instance, those sorts of places that we used to think of as being protected by their remoteness, are increasingly being affected by climate change.

CB: You’ve seen these changes take place while the world has taken relatively little action on climate change. How has that felt?

Glossary

El Niño: Every five years or so, a change in the winds causes a shift to warmer than normal sea surface temperatures in the equatorial Pacific Ocean – known as El Niño. Together with its cooler counterpart, La Niña, this is known as the El Niño Southern Oscillation (ENSO) and is responsible for most of the fluctuations in temperature and rainfall patterns we see from one year to the next.

El Niño: Every five years or so, a change in the winds causes a shift to warmer than normal sea surface temperatures in the equatorial Pacific Ocean – known as El Niño. Together with… Read More

TH: It’s really frustrating. There’s been so little action on climate change. I’ve been studying coral reefs long enough that I can remember a phase of my career before bleaching began. The first records of bleaching were in the El Niño event of 1982-83. That was a real wake-up call. It was the first mass bleaching that we saw as a science community. Places like the Galapagos Islands and Panama were severely affected during that El Niño. We’ve had El Niños forever; they occur on a regular cycle every five years or so. But, it wasn’t until the 1980s and 1990s that El Niños first became dangerous for coral reefs because of the slow underlying increase in temperature due to global warming.

The first global mass bleaching event was in 1998 and that’s when most marine biologists who were active at that time first personally experienced coral bleaching. It’s the first time the Great Barrier Reef bleached. Then it happened on the Barrier Reef four years later in 2002. Then we had a very long gap, a 14-year gap, and we were just simply lucky that we didn’t see the third bleaching event until 2016, and then, unfortunately, we were very unlucky because we saw it for the fourth time just one year later.

What we’ve seen here on the Barrier Reef mirrors the global trend. We’ve gone from a period before the 1980s where mass bleaching simply didn’t happen to an intermediate phase that lasted a couple of decades, where El Niños triggered bleaching. And now more recently, we’re seeing bleaching events throughout ENSO cycles, so even in some neutral years and in La Niña years, which historically were cooler. They’re still cooler than average, but, La Niña periods now, the water temperature is hotter than it was during El Niño phases just 30 years ago.

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CB: I wanted to ask you, in particular, what your thoughts were on the Australian government’s approach to tackling climate change?

TH: Australia’s actually very vulnerable to climate change. We’re vulnerable to droughts, which are exacerbated by elevated temperatures. We’re vulnerable to floods and of course Australia’s coral reefs, which includes lots of reefs in addition to the Great Barrier Reef, are particularly vulnerable to episodes of extreme heat, which we’re seeing more and more of. As a scientist and a member of a large science community, we’ve been talking about coral bleaching; we’ve been studying and measuring it now for 30 years. It is very frustrating that there’s been so little action by the Australian government, who has sole responsibility for stewardship of the Great Barrier Reef world heritage area. You would think that the 1998 event, which killed about 10% of the coral, should have been a wakeup call – but it hasn’t been. Similarly, the reaction to the 2016 and 2017 events was pretty pathetic.

CB: What do you think it is that drives a kind of apathy or scepticism towards climate change in Australia, in particular?

TH: Some politicians are simply climate change denialists. Our current Prime Minister famously brought a lump of coal to Parliament House to spruik [publicise] its importance to the Australian economy. My reading of the politics is there’s a narrowing window of opportunity to dig up as much coal as possible before it’s outlawed as an international commodity and so there’s a huge rush now to develop enormous coal reserves in Australia – that need to be left in the ground if we’re going to have a habitable planet in the future.

There are plans [from Indian mining firm Adani] on the table to develop one of the world’s biggest new coal mines here in Queensland and to export that coal – it’s thermal coal used for generating electricity – across the Great Barrier Reef. The Great Barrier Reef, today, after two back-to-back bleaching events, is in poor condition. The amount of corals out there on the reef is the lowest we’ve ever measured since monitoring began in the 1980s. Now is not the time to develop new coal mines in Australia or anywhere else.

CB:How do you think the debate on climate change compares in Australia to the UK and US, in your opinion?

TH: It’s complicated. We have a dynamic in Australia that I think is quite similar to the US in that our Commonwealth government – our federal government, located in Canberra – has one set of climate policies, whereas the individual states have different policies and, generally, they’re much more ambitious in terms of things like targets for renewable energy. States like South Australia, in particular, but also Queensland and Victoria and Tasmania, are very rapidly making a transition away from fossil fuels. That doesn’t stop some of them supporting export of fossil fuels to some other countries. We’re also seeing more action by individual municipalities and at the household level there’s been a terrific response in Australia. Australia has one of the highest uptakes of domestic solar panels in the world and so most people don’t pay for electricity anymore during the daytime. That’s because in places like Townsville, where I live, we have sunshine for more than 300 days of the year. It’s a no-brainer in terms of saving household income to generate your own electricity from your domestic roof.

CB: You’re very vocal on Twitter. Do you think it’s important for scientists involved with climate change to speak out on Twitter the way that you do?

The days when scientists spoke only to each other in the proverbial ivory tower is, I think, long over. As a climate scientist, I think I have a civic responsibility to communicate to whoever will listen about issues around climate change, particularly climate change and the Great Barrier Reef. The two bleaching events have pretty much changed my life because the public interest in them has been enormous and, certainly not just in Australia, so yes, I use Twitter quite a lot to communicate to people, and I think more and more scientists are doing that. I think it’s important that we get our message across to the general public. I think if we’re going to see action in countries like Australia, it’s going to come from the bottom up – because unfortunately, many politicians don’t believe, and their main interest is getting reelected. If they perceive that the populace, the voters, are more and more aware of climate change and are demanding that politicians do something, then maybe they will.

CB: It was recently announced that the Centre of Excellence for Coral Reef Studies has not been shortlisted for ARC funding. Is that going to affect the centre’s activities?

TH: Our centre is very large. It’s nearly 300 people and we are based in multiple universities around Australia. We’re probably the biggest provider of graduate training, in the coral reef space, in the world. We have more than 150 PhD students. Our budget is quite modest given the scale of our activities. It’s nearly 300 people. We work, in any given year, in about 35 countries – so it’s certainly not just Australia. Our current budget is about $12m [Australian dollars; £6.8m] a year, and our outputs are, I think, pretty impressive. On average, we publish one referee journal article each day, so between 350 and 400 articles a year. The setback we’ve had recently is that we won’t be receiving another seven-year cycle of funding from the ARC’s Centre of Excellence programme, which has funded us for the past 16 years. That represents roughly a 30% loss in our income stream. However, it won’t happen immediately. We’ve got nearly three years to change our funding model and to make up for that shortfall, so it’s not the end of the world by any means. We’ll still continue to be a very considerable force in the research field in coral reefs.

CB: Do you have any thoughts on why that decision to withdraw funding was made?

TH: No. I don’t have any information on that. There’s various conspiracy theories out there, but I can’t shed any light on those. It’s a two-step process. The ARC, the Australian Research Council, invites expressions of interest. They typically get about 120 of them and they select typically about 15 for a short list. Those 15 are invited to provide a full proposal. We, unfortunately, have not been invited to provide a full proposal this time.

CB: The recently released IPCC report on 1.5C found that even if warming is limited to 1.5C, up to 90% of corals will cease to exist as we know them. In light of that, why are coral reefs so vulnerable to warming?

TH: There’s lots of issues to unpack there. The IPCC report projected that 1.5C of global average warming, which could occur as soon as 2030, would likely destroy 70-90% of coral reefs. If we go to 2C, it would likely destroy 99% of coral reefs. I’d seen those figures before because the IPCC processes, they assess the recent scientific literature. As a coral reef scientist, I’m very aware of the coral reef literature. In fact, I’ve written a bit of it. What I learnt most from the IPCC report was the sections on the pathway to net-zero emissions and the urgency of that, which I think was a big part of the report. But, the IPCC did put an emphasis on coral reefs, I think, because of their vulnerability to climate change and their iconic status – everyone knows what a coral reef is – and because so many people, hundreds of millions of people throughout the tropics, depend on coral reefs for their livelihood and for their food security.

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I think the figures – the 70-90% gone with another half a degree of global average warming, above the 1C we’ve already experienced – are on the more pessimistic end of the spectrum. It doesn’t take into account the possibility, or indeed the likelihood, of reasonably rapid adaptation by coral reefs to global warming, so my opinion is a little bit more optimistic in terms of the future trajectory of reefs. I think if we can achieve the 1.5C target, then we will still have coral reefs. I don’t think we’ll lose 90% of them – but they will be quite different from the coral reefs of today and the coral reefs of yesterday.

The reason I’m saying that is the information we’ve garnered from studying places like the Great Barrier Reef for the last 30-40 years. Those reefs are changing. When bleaching occurs, it’s actually incredibly selective. In the science literature, we distinguish between species that are so-called “winners” versus “losers”. The losers are the heat-susceptible ones. Many branching corals, or corals that are the shape of a coffee table, are very susceptible to bleaching. In 2016, about half of those species were killed on the Great Barrier Reef – but the so-called winners are much more resistant. When they do bleach, it takes a lot more heat for them to become pale, they generally regain their colour when the temperatures drop again into wintertime and they survive.

When we studied the back-to-back bleaching on the Great Barrier Reef, we found – and this work will be published very soon – that the response of the corals in the second year was quite different from the first year. The northern Great Barrier Reef was really blitzed in 2016. The average mortality of corals in the eight-month period following the peak temperatures was 51% along the northern third of the Great Barrier Reef that stretches for about 700 kilometers from Papua New Guinea’s south towards the city of Cairns. That area was really badly affected. A year later, the heat returned. In fact, on 80% of the Great Barrier Reef, the temperatures were hotter in 2017 compared to 2016 – but we saw less bleaching in year two. In the north, the reason is not necessarily a good one. The reason it didn’t bleach so much in year two was because all the heat-susceptible ones had died. But the tougher corals that bleached mildly in year one and regained their colour during the winter bleached again quite mildly – and they will also survive as we go through this past winter.

The assumption of many climate models is that the same level of recurrence of heat will have the same biological response and that’s not necessarily true because of this filtering effect that we’re seeing. It also depends on the capacity of the corals to bounce back after a bleaching event. Corals differ in their ability to do that. Some of them make a lot more babies than others. Some of them disperse further – the larvae can go greater distances than others and once they find a reef and settle on it as a juvenile coral, some of them grow a lot more quickly than others. We’re seeing a very rapid change in the mix of species because of the filtering mechanisms. And so that’s why I think we will have a reef in 50 or 100 years time if we can control extreme climate change. But the reef is changing. It’s gone from one system 30 years ago to a different system today and it will continue those sorts of changes.

CB: And will those changes see a reef that is less diverse, or will it just be different species that we’re not used to seeing?

TH: We refer to the period which is now unfolding as the “climate gauntlet” – where the reefs will get worse before they get better. I don’t know that we’ll see species go extinct because coral populations are huge. They’re typically billions of individuals for any one species and they’re very widely distributed. The corals we have here on the Great Barrier Reef, about 100 of those species go as far across the Pacific as French Polynesia.

CB: How are people going to be affected by these changes that we’re going to see to coral reefs? Not just in Australia, but in other countries where people really rely on these reefs.

TH: Here in Australia, or in other wealthy countries like the UK or the US, we tend to value coral reefs for their incredible beauty and, apart from their aesthetic value, we tend to value things like biodiversity or iconic species like turtles and dugongs and so on. But that’s really quite a Western perspective and it’s often coming from people who view coral reefs as a nice warm place to go and have a holiday. But for about 400 million people, coral reefs are on their doorsteps and they have a much more intimate relationship with reefs that’s year-round. Those people depend on reefs for their food security and for their livelihoods, especially through the global coral reef tourism industry. The loss of coral reefs, if you live in London, is something you probably feel sad about, but it’s not going to affect your ability to put a loaf of bread on the table. That’s certainly not the case for many small, often island, nations that are rapidly developing, where coral reefs are an important source of food and an important source of livelihoods.

CB: Finally then, what do you make of the kind of “techno-fixes” that have been proposed to protect the Great Barrier Reef?

TH: I mentioned earlier that Australia’s response to now four bleaching events dating back to 1998 on the Great Barrier Reef has been pretty pathetic. I think because of public pressure – and I’d like to think we contributed to that by speaking about what’s happening to the Great Barrier Reef – there has been significant response by the government, but many people, including myself, are very sceptical about the nature of that. Logically, if climate change is the number-one impact on the Great Barrier Reef, you deal with climate change – but that’s not what’s been happening. Instead, there’s been a ridiculous amount of money, about half a billion dollars, put into a whole crockery of schemes – most of which are pretty laughable.

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There’s a scheme to put fans on one reef near Cairns to try and cool one hectare of it. The Great Barrier Reef is 344,000 sq km in size. It’s about the size of Italy or Japan. So the notion that we can protect the Barrier Reef from the next bleaching event by installing fans on one of the 3,000 individual reefs that makes up the entire Great Barrier Reef is pretty ludicrous. They’re also putting money into floating sunscreen for corals. That’s a chemical that floats on the surface and shades the corals underneath. The problem with that is something called waves and currents – and, of course, the sunscreen breaks down. You would need it to be immobile, the size of Italy, and to last for about two months for it to be effective. An awful lot of money is also going into attempts to control crown-of-thorns starfish [pdf] by injecting them with poison one at a time – and that’s completely ineffective. Those programmes have been in place now for five or more years, and we still have out of control outbreaks of crown of thorns throughout the entire Great Barrier Reef. They can’t be controlled. It’s like running after a plague of locusts with a butterfly net. The root cause of those outbreaks is runoff of pollutants from land that provide more food via plankton for the juvenile starfish. That’s what we should be doing [sic: tackling]. The root causes of the problems of the Great Barrier Reef are pollutants running off from agricultural land, which we can deal with, and climate change – and that’s the elephant in the room which Australia is refusing to deal with.

Volcanologists spent two weeks collecting samples from Yasur, a continuously erupting volcano on Tanna, an island in the remote South Pacific archipelago of Vanuatu,...

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